Getting started This section describes 60 common Linux commands

System information

Arch displays the processor architecture of the machine (1) uname -m displays the processor architecture of the machine (2) uname -r displays the kernel version in use dMIDecode -q displays the hardware system components – (SMBIOS/DMI) hdparm -i /dev/hda List the architecture features of a disk hdparm-tt /dev/sda Perform test reads on the disk cat /proc/cpuInfo Displays CPU info information cat /proc/Interrupts Displays interrupt cat Cat /proc/meminfo Uses cat /proc/swaps to check which swaps are used. Cat /proc/version Displays the kernel version. Cat /proc/net/dev displays network adapters and mounts statistics Lsusb-tv display USB device date Display system date CAL 2007 Display 2007 calendar date 041217002007.00 Set date and time – The month and day are divided into years. seconds

Clock -w Saves the time change to the BIOS

Shutdown (shutdown, reboot, and logout of the system)

Shutdown -h now shutdown the system (1) init 0 shutdown the system (2) telinit 0 shutdown the system (3) shutdown -h hours:minutes & shutdown the system at the scheduled time shutdown -c cancel the shutdown at the scheduled time Shutdown -r Now Restart (1) reboot Restart (2) Logout

Files and Directories

CD /home Go to ‘/ home’ directory ‘CD.. Return to the upper directory CD.. /.. CD to go to the personal home directory CD ~user1 To go to the personal home directory CD – To go to the last directory PWD Display the working path ls View files in the directory ls -f View files in the directory ls -l Display details about files and directories ls -a Display hidden files ls *[0-9]* Display file names and directory names containing numbers tree Display tree structure of files and directories starting from root (1) lstree Display tree structure of files and directories starting from root (2) mkdir dir1 Create a directory called ‘dir1’ Mkdir dir1 dir2 Create both directories mkdir -p/TMP /dir1/dir2 Create a directory tree rm -f file1 Delete a file called ‘file1’ ‘rmdir dir1 Delete a directory called ‘dir1” Rm -rf dir1 Delete a directory named ‘dir1’ and delete its contents rm -rf dir1 dir2 Delete two directories and their contents mv dir1 new_dir Rename/move a directory cp file1 file2 Copy a file cp dir/* . Copy all files in a directory to the current working directory cp -a/TMP /dir1. Copy a directory to the current working directory cp -a dir1 dir2 Copy a directory ln -s file1 lnk1 Create a soft link to a file or directory ln file1 lnk1 Create a physical link to a file or directory touch -t 0712250000 Outputs iconV-l list the known encodedIconV-f of a file or directory fromEncoding -t toEncoding inputFile > outputFile creates a new from the given input file by assuming it is encoded in fromEncoding and converting it to toEncoding. find . -maxdepth 1 -name *.jpg -print -exec convert “{}” -resize 80×60 “thumbs/{}” \; batch resize files in the current directory and send them to a thumbnails directory (requires convert from Imagemagick)

File search

Find / -name file1 Searches for files and directories in the root file system starting from ‘/’. Find / -user user1 Searches for files and directories belonging to user ‘user1’. Find /home/user1-name \* Find /usr/bin-type f-atime +100 Search for the execution file that has not been used in the past 100 days find /usr/bin-type f-mtime-10 Find / -name \*. RPM -exec chmod 755 ‘{}’ \; Find / -xdev-name \*. RPM Find / -xdev-name \*. RPM Find / -xdev-name \*. RPM Ignore the CD drive, flash drive, etc. Locate \*.ps to find a file ending in ‘. Ps’ – first run the ‘updatedb’ command whereis halt to display a binary file, source code, or the location of man which halt Displays the full path to a binary or executable file

Mount a file system

1. Mount /dev/hda2 / MNT /hda2 to mount a disk named hda2 – make sure the directory ‘/ MNT /hda2’ already exists
2. Umount /dev/hda2 Unmount a disk named hda2 from the mount point ‘/ MNT /hda2’
3. Fuser-km/MNT /hda2 Forcibly uninstalls the device when it is busy
4. Umount -n/MNT /hda2 Run the unmount operation without writing to the /etc/mtab file – useful when the file is read-only or when the disk is full
5. Mount /dev/fd0/mnt /floppy Mounts a floppy disk
6. Mount /dev/cdrom/MNT /cdrom To mount a Cdrom or dvdrom
7. Mount /dev/hdc/MNT/cdRecorder to mount a CDRW or DVdrom
8. Mount /dev/hdb/mnt/cdRecorder to mount a CDRW or dvdrom
9. Mount -o loop file.iso/MNT /cdrom To mount a file or iso image file
10. Mount -t vfat /dev/hda5 / MNT /hda5 Mount a Windows FAT32 file system
11. Mount /dev/sda1 / MNT /usbdisk To mount a USB flash drive or flash storage device
12. Mount -t SMBFS -o username=user,password=pass //WinClient/share/MNT /share Mount a Windows network share

Disk space

1. Df -h Displays the list of mounted partitions
2. Ls – lSr | more arranged in size files and directories
3. Du -sh dir1 Estimated disk space used by directory ‘dir1’
4. Du – sk * | sort – rn) based on size, in turn, according to the size of the files and directories
5. RPM – q – a – qf ’10 {NAME} {SIZE} t % % n’ | sort – k1, 1 n based on the SIZE of the display has been installed in turn the space used by RPM package (fedora, redhat class system)
6. dpkg-query -W -f=’${Installed-Size; 10} ${Package} n ‘t | sort – k1, 1 n based on the size of the display installed deb Package used by space (ubuntu, debian system)

Users and Groups

1. Groupadd group_name Creates a user group
2. Groupdel group_name Deletes a user group
3. Groupmod -n new_group_name old_group_name Renames a user group
4. Useradd -c “Name Surname “-g admin -d /home/user1 -s /bin/bash user1 Creates a user belonging to user group admin
5. Useradd user1 creates a new user
6. Userdel -r user1 Deletes a user (‘-r’ excludes the home directory)
7. Usermod -c “User FTP” -g system -d/FTP /user1 -s /bin/nologin user1 Modifies User attributes
8. Passwd Changes the password
9. Passwd user1 Changes the password of a user (root only).
10. Chage -E 2005-12-31 user1 Sets the validity period of the user password
11. PWCK checks ‘/etc/passwd’ for file format and syntax corrections as well as existing users
12. GRPCK checks ‘/etc/passwd’ for file format and syntax corrections as well as existing groups
13. Newgrp group_name logs in to a new group to change the default group for newly created files

File permissions – use “+” to set permissions, use “-” to cancel

1. Ls -lh Displays permissions
2. The ls/TMP | pr – T5 – W $COLUMNS will be divided into 5 bar terminal display
3. Chmod ugo+ RWX directory1 Sets owner (u), group (g), and other (O) permissions for the directory to read (r), write (w), and execute (x)
4. Chmod go-rwx directory1 Deletes the read/write permissions of the group (g) and others (O) on the directory
5. Chown user1 file1 changes the owner attribute of a file
6. Chown -r user1 directory1 Changes the owner properties of a directory and the properties of all files in the directory
7. CHGRP group1 file1 Specifies the group that changes the file
8. Chown user1:group1 file1 Changes the owner and group properties of a file
9. Find / -perm -u+s lists all files in a system that use SUID control
10. Chmod u+s /bin/file1 Sets the SUID bit of a binary file – the user running the file is given the same permissions as the owner
11. Chmod u-s /bin/file1 Disables the SUID bit of a binary file
12. Chmod g+s /home/public Sets the SGID bit of a directory – similar to SUID, except for directories
13. Chmod g-s /home/public Disables the SGID bit of a directory
14. Chmod o+t /home/public Sets the STIKY bits of a file – only allows legal owners to delete files
15. Chmod o-t /home/public Disables the STIKY bit of a directory

File special properties – use “+” to set permissions, use “-” to cancel

1. Chattr +a file1 Files can be read or written in appending mode only
2. Chattr +c file1 allows this file to be automatically compressed/uncompressed by the kernel
3. Chattr +d file1 This file is ignored by the dump program during file system backup
4. Chattr + I file1 is set to an immutable file that cannot be deleted, modified, renamed, or linked
5. Chattr +s file1 allows a file to be safely deleted
6. Chattr +S file1 Causes the system to write the changes to disk as soon as the application writes to the file
7. Chattr +u file1 If a file is deleted, the system will allow you to restore the deleted file at a later time
8. Lsattr displays special attributes

Package and compress files

1. Bunzip2 file1.bz2 unzip a file called ‘file1.bz2’
2. Bzip2 file1 compresses a file called ‘file1’
3. Gunzip file1.gz Unzip a file called ‘file1.gz’
4. Gzip file1 compresses a file called ‘file1’
5. Gzip-9 File1 Maximum compression
6. Rar a file1.rar test_file creates a package called ‘file1.rar’
7. Rar a file1. Rar file1 file2 dir1 Compresses ‘file1’, ‘file2’ and directory ‘dir1’ simultaneously.
8. Rar x file1.rar Decompresses the RAR package
9. Unrar x file1.rar Decompresses the RAR package
10. Tar -cvf archive.tar file1 Creates an uncompressed tarball
11. Tar -cvf archive.tar file1 file2 dir1 Creates an archive file containing ‘file1’, ‘file2’ and ‘dir1’
12. Tar -tf archive.tar displays the contents of a package
13. Tar -xvf archive.tar Releases a package
14. Tar -xvf archive.tar -c/TMP Release the compressed package to the/TMP directory
15. Tar -cvfj archive.tar.bz2 dir1 Creates a compressed package in bzip2 format
16. Tar -xvfj archive.tar.bz2 Decompress a bzip2 package
17. Tar -cvfz archive.tar.gz dir1 Create a compressed package in gzip format
18. Tar -xvfz archive.tar.gz Decompress a gzip package
19. Zip file1. Zip file1 Creates a zip package
20. Zip -r file1.zip file1 file2 dir1 Compresses several files and directories into a zip package
21. Unzip file1.zip Decompresses a zip package

RPM package – (Fedora, Redhat, and similar systems)

1. RPM -ivh package. RPM Installs an RPM package
2. RPM -ivh –nodeeps package. RPM Installs an RPM package and ignores dependency warnings
3. RPM -u package. RPM Updates an RPM package without changing its configuration file
4. RPM -f package. RPM Updates an RPM package that has been installed
5. RPM -e package_name. RPM Deletes an RPM package
6. RPM -qa Displays all installed RPM packages in the system
7. RPM – qa | grep HTTPD shows all name contains “HTTPD” RPM package
8. RPM -qi package_name Gets special information about an installed package
9. RPM -qg “System Environment/Daemons” displays the RPM package of a component
10. RPM -ql package_name Displays a list of files provided by an installed RPM package
11. RPM -QC package_name Displays a list of configuration files provided by an installed RPM package
12. RPM -q package_name –whatrequires displays a list of dependencies that exist with an RPM package
13. RPM -q package_name –whatprovides Displays the volume of an RPM package
14. RPM -q package_name –scripts displays the script L executed during installation/deletion
15. RPM -q package_name –changelog Displays the change history of an RPM package
16. The RPM – qf/etc/HTTPD/conf/HTTPD. Conf the confirmation to the documents provided by which RPM package
17. RPM -qp package. RPM -l displays a list of files provided by an RPM package that has not yet been installed
18. RPM –import /media/cdrom/RPM -gpg-key Import the public KEY digital certificate
19. RPM –checksig package. RPM Verifies the integrity of an RPM package
20. RPM -qa gpg-pubkey Check the integrity of all installed RPM packages
21. RPM -v package_name Check the file size, license, type, owner, group, MD5 check, and last modification time
22. RPM -va Check all installed RPM packages in the system – Use them with caution
23. RPM -vp package. RPM Check that an RPM package is not installed
24. Rpm2cpio package. The RPM | cpio, extract, the make – bin directories * * from a RPM package run an executable file
25. RPM -ivh /usr/src/redhat/rpm/’ arch ‘/package. RPM Installs a built package from an RPM source
26. Rpmbuild –rebuild package_name.src. RPM Builds an RPM package from an RPM source

YUM Package Upgrader – (Fedora, RedHat and similar systems)

1. Yum install package_name Download and install an RPM package
2. Yum localInstall package_name. RPM will install an RPM package and use your own repository to resolve all dependencies for you
3. Yum update package_name. RPM Updates all installed RPM packages in the system
4. Yum update package_name Updates an RPM package
5. Yum remove package_name Deletes an RPM package
6. Yum List lists all packages installed on the current system
7. Yum Search package_name Searches for packages in the RPM repository
8. Yum Clean Packages delete the downloaded packages from the RPM cache
9. Yum Clean headers deletes all header files
10. Yum Clean All deletes all cached packages and headers

DEB packages (Debian, Ubuntu, and similar systems)

1. DPKG -i package.deb Installs/updates a deb package
2. DPKG -r package_name Deletes a DEB package from the system
3. DKG -l displays all deb packages installed in the system
4. DPKG -l | grep HTTPD shows all name contains “HTTPD” deb package
5. DKG -s package_name Gets information about a particular package that has been installed on the system
6. DPKG -l package_name displays a list of files provided by a DEB package that has been installed on your system
7. DPKG –contents package.deb displays a list of files provided by a package that has not yet been installed
8. DPKG -s /bin/ping confirms which deb package is providing the file given

APT software tools (Debian, Ubuntu and similar systems)

1. Apt-get install package_name Install/update a deb package
2. Apt-cdrom install package_name Install/update a deb package from the cd-rom
3. Apt-get Update Updates software packages in the list
4. Apt-get upgrade Upgrades all installed software
5. Apt-get remove package_name Deletes a deb package from the system
6. Apt-get check Verifies that the software repository is correct
7. Apt-get clean Cleans the cache from downloaded packages
8. Apt-cache search searched-package returns the name of the package containing the searched string

Viewing file Contents

1. Cat file1 Forwards the file from the first byte
2. Tac file1 looks at the contents of a file in reverse, starting with the last line
3. More file1 Displays the contents of a long file
4. Less file1 is similar to the ‘more’ command, but it allows the same reverse operation in the file as the forward operation
5. Head-2 file1 Displays the first two lines of a file
6. Tail-2 file1 Displays the last two lines of a file
7. Tail -f /var/log/messages View the contents added to a file in real time

Text processing

1. cat file1 file2 … | command <> file1_in.txt_or_file1_out.txt general syntax for text manipulation using PIPE, STDIN and STDOUT
2. cat file1 | command( sed, grep, awk, grep, etc…) > result.txt merges the detailed text of a file and writes the introduction to a new file
3. cat file1 | command( sed, grep, awk, grep, etc…) >> result.txt merges the detailed text of a file and writes the introduction to an existing file
4. Grep Aug /var/log/messages Find the keyword “Aug” in the file ‘/var/log/messages’
5. Grep ^Aug /var/log/messages Look for words starting with “Aug” in the file ‘/var/log/messages’
6. Grep [0-9] /var/log/messages Select all lines containing numbers in the ‘/var/log/messages’ file
7. Grep Aug -r /var/log/* Search for the string “Aug” in the directory ‘/var/log’ and subsequent directories
8. Sed ‘s/stringa1/stringa2/g’ example. TXT replace “string1” in example. TXT with “string2”
9. Sed ‘/^$/d’ example.txt deletes all blank lines from example.txt
10. sed ‘/ *#/d; /^$/d’ example.txt Removes all comments and blank lines from example.txt
11. Echo ‘esempio’ | tr / : the lower: ‘ ‘[: upper:]’ merger and content of cells
12. Sed -e ‘1d’ result. TXT excludes the first line from the file example. TXT
13. Sed -n ‘/stringa1/p’ looks at lines containing only the word “string1”
14. Sed -e ‘s/ *$//’ example. TXT deletes the whitespace character at the end of each line
15. Sed -e ‘s/stringa1//g’ example. TXT deletes only the word “string1” from the file and keeps all the rest
16. Sed – n ‘1, 5 p; 5q’ example.txt Displays the contents from line 1 to line 5
17. sed -n ‘5p; 5q’ example.txt Look at line 5
18. Sed -e ‘s/00*/0/g’ example.txt replaces multiple zeros with a single zero
19. Cat -n file1 indicates the number of lines in a file
20. The cat example. TXT | awk ‘NR % 2 = = 1’ delete example. All even lines of the TXT file
21. Echo a b c | awk ‘} {print $1 to check the line of the first column
22. Echo a b c | awk ‘{print $1, $3}’ see a row of the first and the third column
23. Paste File1 file2 Combines the contents of two files or columns
24. Paste -d ‘+’ file1 file2 Combines the contents of two files or columns with “+” between them
25. Sort file1 file2 Sorts the contents of two files
26. Sort file1 file2 | uniq took out two file and set the line only keep a (repeat)
27. Sort file1 file2 | uniq -u delete intersection, leaving the other line
28. Sort file1 file2 | uniq – d out the intersection of two files (leaving only exists in two files in the file at the same time)
29. Comm-1 file1 file2 Compares the contents of two files and deletes only the contents contained in ‘file1’
30. Comm-2 file1 file2 Compares the contents of two files and deletes only the contents contained in ‘file2’
31. Comm-3 file1 file2 Compares the contents of two files and deletes only the common parts of the two files
32. Ps – ef | grep procedure_name | grep -v grep | awk ‘{print $2}’ | xargs kill 9 kill process according to the process name
33. Ps – ef | grep procedure_name | awk ‘{print $2}’ process by process name
34. Ps – ef | grep udpserver | grep Java | awk ‘{print $2}’ increased filter results: returns a process, for the udpserver process. (Multiple filter conditions can be added as required)

Character Settings and file format conversion

1. TXT Fileunix. TXT converts a text file format from MSDOS to UNIX
2. Unix2dos fileunix.txt Converts a text file from UNIX to MSDOS
3. recode .. HTML < page.txt > page.html converts a text file to HTML
4. Recode – l | more show all allow conversion formats

File System Analysis

1. Badblocks -v /dev/hda1 Check the bad magnetic blocks on disk Hda1
2. FSCK /dev/hda1 Fixes/checks the integrity of the Linux file system on the hda1 disk
3. Ext2 /dev/hda1 Repair/check the integrity of the ext2 file system on the hda1 disk
4. E2fsck /dev/hda1 Repair/check the integrity of the ext2 file system on disk hda1
5. E2fsck -j /dev/hda1 Restores/checks the integrity of the ext3 file system on hda1
6. Ext3 /dev/hda1 Repair/check the integrity of the ext3 file system on the hda1 disk
7. Fsck. vfat /dev/hda1 Repair/check the integrity of the FAT file system on hda1
8. Fsck.msdos /dev/hda1 Fixes/checks the integrity of the DOS file system on the hda1 disk
9. Dosfsck /dev/hda1 Fixes/checks the integrity of the DOS file system on the hda1 disk

Example Initialize a file system

1. MKFS /dev/hda1 Creates a file system in the hda1 partition
2. Mke2fs /dev/hda1 Creates a Linux ext2 file system in the hda1 partition
3. Mke2fs -j /dev/hda1 creates a Linux ext3(journaling) file system in the hda1 partition
4. MKFS -t vfat 32 -f /dev/hda1 Creates a FAT32 file system
5. Fdformat -n /dev/fd0 Formats a floppy disk
6. Mkswap /dev/hda3 Create a swap file system

SWAP file system

1. Mkswap /dev/hda3 Create a swap file system
2. Swapon /dev/hda3 Enables a new swap file system
3. Swapon /dev/hda2 /dev/hdb3 Enable two swap partitions

The backup

1. Dump-0aj -f/TMP /home0.bak /home Make a full backup of the ‘/home’ directory
2. Dump-1aj -f/TMP /home0.bak /home Make an interactive backup of the ‘/home’ directory
3. Restore-if/TMP /home0.bak Restores an interactive backup
4. Rsync-rogpav –delete /home/tmp To synchronize the directories on both sides
5. Rsync-rogpav -e SSH –delete /home ip_address:/ TMP Rsync through the SSH channel
6. Rsync-az -e SSH –delete ip_addr:/home/public /home/local To synchronize a remote directory to the local directory through SSH and compression
7. Rsync-az -e SSH –delete /home/local ip_addr:/home/public To synchronize the local directory to the remote directory through SSH and compression
8. Dd bs = 1 m if = / dev/hda | gzip | SSH user @ ip_addr ‘dd of = hda. Gz’ via SSH on a remote host to perform a backup of the local disk operations
9. Dd if=/dev/sda of=/ TMP /file1 Backs up the disk content to a file
10. Tar -puf backup.tar /home/user Perform an interactive backup operation on the ‘/home/user’ directory
11. (CD/TMP/local / && tar c.) | SSH – c user @ ip_addr ‘CD/home/share / && tar x – p’ via SSH to copy a directory content in the remote directory
12. C/home (tar) | SSH – c user @ ip_addr ‘CD/home/backup – home && tar x – p’ via SSH in the remote directory copy a local directory
13. tar cf – . | (cd /tmp/backup ; Tar xf -) locally Copy a directory to another location, keeping the original permissions and links
14. Find/home/user1 -name “*.txt ‘| xargs cp – av — target – directory = / home/backup / — parents from a directory to find and copy all in’. TXT ‘ End the file in another directory
15. Find/var/log – the name ‘*. The log’ | tar CV – files – from = – | bzip2 > the tar. The.bz2 find all to ‘log’ at the end of the file and make a bzip package
16. Dd if=/dev/hda of=/dev/fd0 bs=512 count=1 Copy the contents of the MBR (Master Boot Record) to the floppy disk
17. Dd if=/dev/fd0 of=/dev/hda bs=512 count=1 Restore the MBR content from the backup saved to the floppy disk

CD

1. Cdrecord -v gracetime=2 dev=/dev/ cdrom-eject blank= fast-force Clears the contents of a reproducible CD
2. Mkisofs /dev/cdrom > cd.iso Create an ISO image file on the disk
3. Mkisofs/dev/cdrom | gzip > cd_iso. Gz on disk to create a compressed the cd-rom iso image files
4. Mkisofs-j-allow-leading-dots -r -v “Label CD” -iso-level 4 -o./cd.iso data_cd Creates an ISO image file for a directory
5. CD record -v dev=/dev/cdrom cd.iso Burns an ISO image file
6. Gzip – dc cd_iso. Gz | cdrecord dev = / dev/cdrom – burn a compressed the ISO image file
7. Mount -o loop CD. Iso/MNT /iso Mount an ISO image file
8. Cd-paranoi-b transcribe audio tracks from a CD to a WAV file
9. Cd-paranoia — “-3” transcribe audio tracks from a CD to a WAV file (parameter -3)
10. Cdrecord –scanbus scans the bus to identify SCSI channels
11. Dd if = / dev/HDC | md5sum check md5sum encoding of a device, such as a CD